The Mechanics of You
by PangeaSplits
Summary: He knocks Charles' sword out of his hands with a deft twist of his own, metal colliding with metal in a very satisfying clash that vibrates through Erik's senses, jarring in a pleasant way. With Charles, he has found his polar opposite and his perfect fit. Charles/Erik.


Birthday!fic for **Ninemoons42**.

Disclaimer: I own nothing.

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_**The Mechanics of You**_

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Metal, Erik thinks, likes to sing.

_That's poetic_, Charles interjects, because he's always listening in, _I didn't think you were the type_.

_It was a feeling_, Erik retorts coolly, but not without a small wave of not-so-hidden amusement, _not a fully-formed thought._ Aloud, he adds, "You're paying attention to the wrong side of my brain."

And then he knocks Charles' sword out of his hands with a deft twist of his own, metal colliding with metal in a very satisfying clash that vibrates through Erik's senses, jarring in a pleasant way. Charles' sword arcs back through the air and lands on the practice mats a few feet away, out of reach.

Erik moves the point of his own sword up to Charles' throat lazily, a mere breath away from scratching his pale skin. The telepath is flushed and panting with exertion, sweat plastering his hair down against his forehead in wild disarray, blue eyes flashing with the reflection of steel.

"Check." Erik gives him a smug smile, all teeth. "You still favor your right side too much."

Charles, because he is petty, freezes him.

"Mate," he says calmly, stepping around Erik's sword, walking along the length of it so closely he's in danger of cutting his cheek, "and I'm not petty, you're just being a poor sport."

If Erik could roll his eyes, he would. As it stands, he can only remain how he is, sword extended elegantly, his muscles only tense because they're being forcibly held in place. He can feel his own sweat, even in the cool air-conditioning of the practice room, rolling down his spine slowly; beside him, Charles shivers for him.

"One more round?" Charles asks aloud, reaching up to wrap both his hands around Erik's hand at the hilt of the sword. He's smiling, eyes bright and alive, and for a split second Erik can see his face from six months ago, dull-eyed and pale, and the contrast is so startling that for a moment the metal-bender is breathless.

_Since I'm so able to say no to you_, Erik thinks at him frostily, but underneath that his true thoughts give him away, pulsing with warmth and _yesofcourseanythingforyou_.

Fortunately Charles can hear all of it, the many layers of Erik's mind, and doesn't need Erik to make enough sense of his often-tangled thoughts and feelings when it comes to Charles to actually say the words aloud; he understands Erik sometimes far better than Erik suspects he can understand himself.

Charles' smile is gentler, but no less fond. He presses a small kiss to the side of Erik's hand and then steps back, retreating the scant few paces in order to bend down and pick up his own sword, a perfect twin to the one Erik holds. He lifts the blade, arm muscles flexing, crossing it with Erik's. "En garde, my friend."

He drops his unbreakable hold on Erik, and Erik snorts as he knocks Charles' blade aside and thrusts his own forward immediately, springing into action. Charles ducks as he takes a step back, swiping at Erik's flank to force the metal-bender to change tactics and swing his blade around for a parry, blocking the attack.

"We," Erik tells him crisply, "are not fencing."

Charles' laugh is mostly silent, ringing through Erik's mind cheerfully as Erik puts the telepath through his paces, always attacking. Erik's always been aggressive, it's in his very demeanor, and he refuses to back down, relying on his superior height to force Charles into spending more time defending than attacking back. Charles counters him, not without effort or flaw, but Erik can feel himself beginning to wear down as he tries to sneak his blade through Charles' considerable defenses.

With Charles, he has found his polar opposite and his perfect fit.

Erik's blade hums to his sense as he cuts through the air, going for Charles' elbow first only to change direction when the telepath anticipates his move—he'll have to trust that Charles is reading his body language this time, and not his mind—and instead slashes at Charles' stomach. Charles blocks him, only barely, their swords scraping together loudly in a song that Erik can feel in his bones.

Charles knocks him back, taking a step backwards to add more distance between them, gripping his sword in front of him with both hands. He's panting, out of breath, so Erik lets him breathe and takes a moment to catch his own, reveling in the adrenaline coursing through his body. They're only able to spar with real swords like this because of his ability—no metal will ever truly cut Charles, not while he's watching—and he loves how heightened his senses become during these precious hours of swordplay, when it's just him, Charles, and metal dancing together.

"Careful," Charles teases, though he sounds terribly fond, "you're letting your sentiments show."

"Focus on the physical, Charles," Erik says, slamming his blade down on top of the telepath's so hard that for a split second he can feel the steel waver, "not the mental."

Charles grits his teeth, swinging his blade out from underneath Erik's in a neat arc in another divine scrape of metal-on-metal, but silently he's scoffing_. As if I'd ever ask you to stop listening to your metallic symphony. _

He saves Erik from answering by starting off his own round of attacks, pushing Erik back towards the center of the practice mats. His movements are elegant and sure, a far cry from when they'd first picked up the blades together; Charles shaky and unsure on his legs and Erik just as unsure as to how to make it better.

_You're being maudlin, darling_, Charles murmurs, even as Erik has to duck and parry to avoid getting his throat torn open, _those days are long since gone._

_I'm glad, _Erik admits, jabbing down towards Charles' thigh because the telepath always forgets to guard his lower body and could use the reminder.

If the swords sing to Erik, Charles' legs are an entire orchestra, that light up in his mind like two side-by-side supernovas. Outwardly, his legs appear no different than they always used to be, strong and compact with miles of pale skin, but beneath that, invisible to everyone but Erik, is the true miracle of Charles' legs—smooth metal and flawless hydraulics, replacing bone and muscle.

The corners of Charles' lips are quirked upwards in a smile, and then the telepath bends his knees and _leaps_, clearing Erik's full height with plenty of room to spare, landing easily with perfect balance directly behind the metal-bender, his sword tip brushing the back of Erik's neck.

"You're paying attention to the wrong half of my body," Charles teases, the smile evident even in his voice, "dance with me?"

Erik smirks. "My pleasure, vicar."

He whirls around and their blades meet with a loud clang, and together they fall into the same steps of a dance that only they can perform; Charles more mobile because of his bionic legs, and Erik able to keep up because of his absolute mastery over his powers.

They exchange a flurry of fast blows in midair, blades moving in blurs, trusting each other to be able to keep up, because the goal of this isn't to harm, isn't even to give Charles practice with his mobility—he's long since graduated from the grueling physical therapy that came along as a package deal with his replacement legs—but instead it's all about falling into sync with each other, achieving that perfect serenity where they fall into place, past Charles' shortcuts of reading minds, where even Erik can reach; where they don't need words or even thoughts, in this case, to know each other inside and out.

Erik stands on air, the magnetic currents in the room bowing to his will, and Charles jumps up to meet him, slashing at his chest as he springs past. If Erik wanted he could stop Charles, catch him by the legs so together they'd be floating, but if there's one thing he'll never do, it's impeding Charles' free will to move—the telepath has already had that stolen once, and Erik has already made a vow of never again.

_That's silly_, Charles says, because he's incurably nosy when it comes to Erik's thoughts, _you take full pleasure in pinning me down for—_

_Oops_, Erik thinks pleasantly as he knocks Charles out of the air with one well-aimed slash of his blade; Charles has to counter and take the fall, or risk losing his arm.

"Now that was hardly fair," Charles protests, slightly winded, even as he takes a few graceful, bouncing steps. He looks like he's walking on the surface of the moon.

"Keep your focus," Erik tells him, and isn't allowed to finish the rest of his lecture when Charles attacks again, forcing him to drop down a few feet in order to keep his balance after an uppercut from Charles nearly sends him reeling.

Charles lands again, always on his feet like a cat. He gives his sword a lazy twirl. "Come down here."

Erik surveys him for a moment; he's still light and teasing, but all the jumping around is definitely costing him; his breathing is a little unsteady as he pants, his sweat soaking through his shirt. It's good for Charles to test himself, to see how far he can push his body, both natural and robotic but _all_ man-made—Charles chuckles at this—but Erik figures that he's nearly at his limit for the day, and there's no need to push past it yet, so he allows himself to drift down, feet settling on the practice mats.

"That's better," Charles says, and this time it's Erik's turn to interrupt him, attacking him with a new burst of energy, pressuring him back now that they're on equal footing again, a whole new kind of dance.

Erik's sword arm is trembling with exertion but he keeps his grip on the hilt, even though he doesn't need to physically hold on to it to be effective in his skill. He likes the feel of the metal in his hand, how the sword has become an extension of his own arm, almost as if he's matching Charles' legs; though his version is much more crude.

_I like you whole_, Charles muses, on the offensive now, and Erik catches his train of thought as an echo, thinking of people who willingly undergo the bionic surgeries, _I don't taste the metal like you do._

Erik plants his feet, refusing to retreat another step, deflecting Charles' triple slash with neat precision. His feet don't stay still for long, because if there's one thing he's drilled into both himself and Charles is that footwork, and constant motion, is the key to victory.

And Charles can move, now; something that both of them take fierce, delighted pride in; after the accident nearly a year ago that left Charles' legs crushed and mangled—he had survived, barely, and was left to live in chronic pain with no hope of walking ever again.

Their fight about considering bionic legs as replacements had lasted a week.

It had been ugly, both of them saying things that they'd each come to regret later, at different times, and sometimes Erik still feels that they're slowly getting back into the sway of things now in the aftermath, testing out the waters of what their relationship has become. It's part of each of their natures, to push at each other, chaffing against one another even when they both know that they already fit—perfectly because of their imperfections.

_Sometimes I think you love me better because of the legs_, Charles gets in quietly, a small tendril of thought that snakes its way into Erik's brain until it's reverberating back and forth so loudly that he may as well have shouted it out loud.

Erik comes to a dead halt, his focus on the sparring match lost completely, and doesn't even react when Charles naturally takes advantage, knocking Erik's blade up out of his hand, sending it clattering down onto the practice mat, holding his own sword flat against the metal-bender's throat. They're both panting, their faces inches apart, holding each other's gaze unblinkingly—this close, Charles' eyes could be bottomless.

"Is the metal in your brain," Erik says aloud, because some things Charles needs to _hear_, not glean. He's not angry, not quite—in another time and place, perhaps he would have been, but here and now, all he wants to do is make Charles understand.

Charles remains unblinking, proudly defiant. "I hear your thoughts. These legs of mine—" he shifts his stance ever so slightly and this close, Erik can hear the quiet, barely-audible whirl of the gears and joints moving in tandem, and Erik can feel each and every one in minute detail, "—are like focal points for you." He isn't quite angry either—he wants to understand, he's waiting for Erik to tell him.

Erik shakes his head, unheeding of the blade still at his throat. "That's like asking you to tune out all the minds you overhear. I don't love you for your mechanical legs—I love you for the mechanics of _you_."

It's not an elegant declaration, but Erik's never been one for poetry anyway; he speaks how he means to, and can only hope that Charles, at least, will understand—if no one else, only Charles.

And the telepath does, because he's smiling again, softer than before; more privately as he soaks in all the other things Erik has left unsaid between them, gathering in the metal-bender's full meaning, leaving no room for any other doubts. He lets his sword drop, stepping up even closer to Erik so that they're pressed close, chest-to-chest, head tilted back so he can still meet the metal-bender's gaze.

"You sure do know how to charm, with those lines of yours," he says with a grin.

"You fall for them," Erik says, rolling his eyes this time because he actually can, "and as if you're one to even talk."

"Shut up," Charles says, and then he's reaching up to wrap his hand around the back of Erik's head, fingers curling in the metal-bender's damp hair, guiding Erik down.

Erik goes willingly, bending to slant his mouth across Charles' and kisses him long and deep, his hands sliding up to rest on the telepath's back, gentle hold morphing into firm grip as they grow more insistent, tongues sliding together in wet warmth, and if Erik could pick a taste to live on for the rest of his life, it would only have to be Charles.

Charles drops his sword and Erik kicks it away with no concern for the sharp blade, sending it skittering across the mats towards where his lies, gladly bearing Charles' weight when the telepath shifts to clutch at him, hands fisting in the front of Erik's shirt as they continue their kiss, stretching up as far as he possibly can, and Erik can feel Charles' mind brushing against his own, a warm buzz of thoughts and feelings rebounding between them as they soak each other in.

Erik rests his forehead against Charles' when they finally break apart, closing his eyes for a moment as he breathes. They're both sweaty and disgusting, and Charles needs to go through his cool-down motions before they can consider cleaning up, but they can always start that in a bit.

"Forget the cool-down," Charles mumbles dismissively, "I have a _far_ better idea." He shares it, the images flashing through Erik's mind and making him snort.

"You give your flexibility far too much credit," he murmurs, but his hands have started to creep lower down the telepath's spine, almost to the point where Charles' flesh ends and his machines begin.

"I think I know perfectly well what I'm capable of," Charles answers, his amusement wicked, "and don't even deny that now you're curious. You. Me. Shower. Now."

Erik laughs, a low rumble of sound, but he detaches himself from the clinging telepath, instead taking one of Charles' hands in his own, lacing their fingers together and giving his hand a small squeeze. They're still figuring things out, he thinks as they walk together off the mats side-by-side, passing their dropped swords, the blades crossed in an _X_, but he's not worried—they go together, and like well-oiled machinery, all the kinks will be worked out until they run nothing but smooth.

_And a little rough every now and then_, Charles adds, grinning mischievously, because he's incorrigible.

Erik sighs, but projects his wave of unabashed fondness loud and clear, and together they walk out of the practice room, moving as one.


End file.
